EAL Idea - is this even possible?

[kaiserwilhelm]

Paragraph of text. 3 lines of which are underlined the same color as the text.
So, Black / Black
Can I make an EAL to "find" the underlines and change to blue?

 

[Joe]

If the underline is a stroke you can tell it to change black strokes only. (I think)

 

[abc]

The selection is the tricky part.
You need to find a way to select only those you want to change.
So maybe length, thickness, color, position.
You need a unique combination which will only select what you need to change!